I like to read books that talk about recipe designing. "Designing Great Beers" by Ray Daniels is a good one. For extract brewing, I really like "Brewing Classic Styles" by Jamil Zainasheff and John Palmer. Another helpful thing is to look at the BJCP guidelines: BJCP Style Guidelines
That will help you determine what a "hoppy" beer tastes like, and still be in style guidelines.
I also use Beersmith, the software program. It's free to try, and it has a list of ingredients that has a short description of each. It helps you think about each ingredient and what it brings to your recipe.
I suggest trying simple recipes, with only a couple of different specialty grains and hops. This keeps the beer from tasting "muddy" as well as shows you what individual ingredients do. Some grains are "malty", some are "sweet", some are "toasty", etc.
You could actually stop making kits now, and follow a simple extract recipe. Let us know if you want some help!
One other thing that really helps- taste the grains! Say you have a recipe with some crushed grains to steep. Before you mix them, taste them individually. That will give you a great idea of what they taste like and what they will bring to the beer.